Open surgical procedures which require incisions through skin, tissue, and organs have a traumatic effect on the body and can lead to substantial blood loss. In addition, such procedures expose tissue and organs to the outside environment which creates an increased risk of post-operative infection. After open surgical procedures, patients are generally in pain, require substantial recovery time, and are susceptible to post-operative complications. As a result, open surgical procedures are generally higher in cost and have a higher degree of risk.
Because of the problems associated with open surgical procedures, the use of minimally invasive surgical techniques has grown substantially over the recent years. As these techniques have developed, the number and types of treatment devices, including vessel closure members, have proliferated. Vessel closure members are generally used for sealing fluid passageways in patients, including but not limited to, percutaneous sites in femoral arteries or veins resulting from intravascular procedures, cardiovascular deformations, fallopian tubes and the vas deferens to prevent conception, and vessels in the brain. Recently, much focus has been placed on developing closure members which allow quicker hemostasis during intravascular procedures and closure members which quickly and effectively occlude fallopian tubes or the vas deferens to prevent conception.
Intravascular Closure Members
One of the important benefits of minimally invasive intravascular procedures is less patient blood loss; however, particularly in procedures in which the femoral artery is accessed, achieving quick and effective hemostasis at the puncture site still can be problematic. More recently, the increased use of heparin and larger sized introducer sheaths have presented additional challenges. When larger devices are introduced into an artery or vein, e.g., 5 Fr or larger, external manual or mechanical compression applied at the entry site, commonly the femoral artery or vein, has been the standard method of achieving hemostasis, which occurs when a thrombus forms at the vessel opening, thereby preventing further bleeding at the site. External compression typically requires that the constant, firm pressure is maintained for up to 30 minutes until hemostasis has been achieved. Even after hemostasis, the site remains vulnerable to further bleeding, especially if the patient is moved.
To address the obvious inadequacies of using manual or external compression alone to close a percutaneous site, a number of devices have been developed to assist in closure of the entry site. Various suturing devices have been developed by Perclose, Inc. and sold by Abbott Laboratories (Redwood City, Calif.) which deliver needles that penetrate the arterial wall to form a knot to close the puncture site. While suturing produces relatively quick and reliable hemostasis when compared to external compression, it is a technique that requires much skill and experience on the part of the physician. In addition, the complexity of the device has led to reports of failures such as in the ability to form a proper knot and other problems. Another known complication is when the device is deployed such that the needles penetrate completely through the opposite wall of the target vessel, which can inadvertently lead to the vessel being closed off, a potentially serious event for the patient.
Hemostatic collagen plugs offer a lower cost, simpler alternative to suturing devices and they have increased in popularity, particularly the VASOSEAL® (Datascope Corp., Montvale, N.J.) and ANGIOSEAL™ (The, Kendall Co., Mansfield Mass.) closure devices. VASOSEAL® comprises a bovine collagen sponge plug that is pushed through a blunt tract dilator through the tissue puncture channel where it is deployed against the outer vessel wall to seal the puncture site. The collagen plug swells with blood and helps occlude blood flow. Manual pressure is still required following initial hemostasis until thrombosis formation is sufficient. Complications can occur from the dilator entering the vessel where the collagen can be accidentally deployed. Placement of the device also requires that the depth of the tissue channel be pre-measured to achieve satisfactory placement. The ANGIOSEAL® device is similar except that it includes a prosthetic anchorplate that is left inside the vessel where it biodegrades in about 30 days. Re-puncture at the site can typically occur at that time at the site, but may be problematic if the anchor device has not been reabsorbed. Additionally both closure devices, being made of bovine collagen, can cause the formation of fibrotic tissue in some patients, which in severe cases, has been known to be sufficient to restrict blood flow within the vessel. A third device utilizing collagen is the DUETT™ sealing device (Vascular Solutions Inc., Minneapolis, Minn.), which comprises a balloon catheter that delivers a collagen and thrombin solution to the puncture site, which causes fibrinogen formation that seals the puncture site. Generally, collagen plugs have been of limited use in closing larger punctures sites and are typically intended for procedures involving 5-8 Fr introducer sheaths. Even suturing devices are intended for closing puncture sites in the small to moderate range, although some physicians have reportedly been able to perform an additional series of steps to suture larger arterial puncture sites, adding to the time and complexity of the procedure.
Fallopian Tube Closure Members
Currently available methods for permanently occluding or closing fallopian tubes and the vas deferens to prevent conception include tubal ligations and vasectomies. Both of these procedures, however, are invasive, are not generally performed in the doctor's office, and can be expensive. Prior art methods of occluding the fallopian tubes include placing an elastomeric plug or other member in the isthumus or narrow most portion of the fallopian tubes. These elastomeric plugs or other members, however, often migrate in the fallopian tube or otherwise become dislodged allowing sperm to pass through the fallopian tube and fertilize an egg released by an ovary. Another prior art fallopian tube occlusion device is disclosed in Nikolchev et al., U.S. Pat. No. 6,176,240 B1. Nikolchev et al. discloses a metallic coil which is pre-shaped into multiple loops separated by straight sections or pre-shaped into a “flower coil.” The metallic coil is inserted into the fallopian tube in an elongated state and when deployed returns to the “flower coil” shape which has a larger diameter than the fallopian tube. The fallopian tube occlusion device of Nikolchev et al. is complicated requiring the metallic coil to be pre-formed into a flower shape which must have a diameter larger than the interior of the fallopian tube, or the device will not lodge in the fallopian tube.
What is needed is a simple to use, relatively inexpensive, closure member that can provide safe and efficient closure of both smaller and larger vessels, including femoral veins and arteries, fallopian tubes, and the vas deferens. Ideally, such a member should be compatible with other instrumentation used in the procedure, it should be highly biocompatible, and it should allow subsequent access at the entry site after a reasonable period of time without further complications. In addition, the closure member should be designed for use with a delivery system that allows precise placement without having to pre-measure the tissue channel leading to the vessel, permits the closure member to be reliably placed in the desired location, and delivers the closure member easily and reliably in the vessel or against the vessel wall.